Interpretive Summary: Leptin is a hormone produced by adipose tissue that can affect feeding behavior, animal health and reproduction. Studies in rodents have demonstrated that leptin can reduce fat mass. This experiment was designed to determine if porcine leptin can alter lipid synthesis in the adipose tissue. The data in the present study indicate that leptin can directly inhibit lipogenesis in porcine adipocytes. These data also demonstrate leptin functions to promote the partitioning of energy away from lipid accretion within porcine adipose tissue, in part by reducing insulin- mediated stimulation of lipogenesis. This action of leptin may be useful in a pharmacological approach to reducing fat mass in swine.